Viscosity drop why?

[Herman]

On a recent sample I ran on a 15w40 conoco my Vis dropped to 10.10 with no antifreeze contamination and fuel within limits at 0.50, What could cause this drop?

 

[Pablo]

That is a huge drop. Is your UOA posted?

Mostly shearing, I presume. How many mega miles, car, engine,etc???

 

[Herman]

John Deere tractor 4320, diesel engine, 200 hours. I do not know how to post a UOA.

 

[bruce381]

good to know virgin vis maybe you got a bad batch maybe lab is wrong maybe???
always run a virgin sample.
bruce

 

[PT1]

Was the oil more than 2 years old and kept in a cold garage? you could have additives that dropped out of solution.

 

[Herman]

I buy a 275 gallon tote of oil every 3 months, so sitting not a problem. Virgin vis of 16.1. Other samples on different machines with this batch fine at 14.5 to 15 . but this tractor came back low last 2 samples.

 

[PT1]

I would take it back and call the company's customer service line and get your money back.

 

[Rand]

I dont see what help that would be.
he states he buys 275gallons every 3months.. it works fine in other equipment.. obiviously something in the JD is shearing it down. What about fuel contamination(sp?) I dont know much about that series what kind of engine is that.. some sort of turbo diesel?

 

[Pablo]

Probably best if we see the whole analysis. The engine is shearing the oil, as to why - I just don't know this engine.

Post it here:

http://theoildrop.server101.com/forums/postlist.php?Cat=0&Board=UBB26

Just copy someone else's typed analysis - paste in a new thread then insert your numbers, etc. Easy pie.

Also consulting Terry at http://www.dysonanalysis.com/ is advised.

 

[bruce381]

Quote:

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I buy a 275 gallon tote of oil every 3 months, so sitting not a problem. Virgin vis of 16.1. Other samples on different machines with this batch fine at 14.5 to 15 . but this tractor came back low last 2 samples.

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Since a 15/40 starts with about a 10 cSt base oil I doubt you can shear it back to just base oil vis. So that leaves lab test, sample error or wrong oil vis used in that unit or tote is a 10/30 and is mislabled tho you said other units are fine with I assume "same tote of oil".
Maybe someone topped ot that one with Hydro oil??
bruce